High security lock and key blade combination

ABSTRACT

A high security cylinder lock ( 1 ) and key ( 2 ) combination comprising a cylindrical shell ( 140 ), a key plug ( 130 ) which is rotatably mounted in the shell ( 140 ), a longitudinal key slot ( 100 ) in the key plug, and at least one locking tumbler assembly cooperating with a key being inserted into the lock. The locking tumbler assembly comprises a pair of independently movable tumbler segments ( 113, 114 ) which are positionable in different elevational positions in a common cavity.

FIELD OF THE INVENTION

The present invention concerns a cylinder lock and key combinationcomprising a cylinder shell, a key plug which is rotatably mounted insaid shell, a longitudinal key slot extending along said key plug inparallel to the rotational axis for receiving a key blade having, at aside surface thereof, a longitudinally extending coded surface, at leastone locking tumbler assembly having a body segment with a contactportion reaching into said key slot so as to engage with said codedsurface of a properly shaped key blade upon insertion thereof into saidkey slot, and at least one cavity located at a transversal side of saidkey slot in said key plug, said cavity accommodating an associated oneof said at least one tumbler assembly and guiding the latter forelevational movement therein.

BACKGROUND OF THE INVENTION

Such a lock is previously known from the patent specifications U.S. Pat.Nos. 4,756,177, 4,815,307, 5,640,865 and 5,067,335 (all in the name ofWidén). In the locks disclosed in these references, each tumblerassembly has a finger portion projecting outwardly therefrom, either indifferent angular directions or at different positions, such that thelongitudinal distribution of the outer ends (contact portions) of thefinger portions generally differs from the normally regular distributionof the locking tumblers themselves in the longitudinal direction, i.e.in parallel with the key slot.

In this way, the number of code combinations can be made very high. Eachtumbler assembly is elevationally movable in the associated cavity and,in addition, the specific position of the contact portion in saidlongitudinal direction along the key slot provides further codepossibilities.

These known locks provide a great number of code combinations, and alsoa high security against picking.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a high security lockand key combination of the aforementioned kind with a locking mechanismhaving at least the same high number of code combinations as the knownlocks and providing an even higher security against picking.

According to the present invention, this object is achieved for a lockof the aforementioned kind in that at least one locking tumbler assemblyof the lock comprises a pair of adjacent tumbler body segmentsaccommodated in the same cavity, each tumbler body segment having acontact portion (not necessarily in the form of a finger) reaching intothe key slot. The adjacent tumbler body segments in said pair are guidedin said cavity for elevational movement independently of each other. Theadjacent body segments in the pair are individually displaced intorespective elevational positions while being engaged, at said contactportions, by said coded surface upon insertion of said key blade intosaid key slot. Also, the associated contact portions in the pair areaxially separated in the longitudinal direction of the key plug suchthat these contact portions will be positioned at elevationally specificand generally different levels when being engaged by the coded surfaceupon insertion of key blade into the key slot.

The U.S. Pat. No. 2,155,734 discloses a similar lock and key systemwhere each tumbler assembly comprises a pair of adjacent tumblersegments. However, these segments in a pair are coupled to each other bya spring acting to separate the two segments in opposite direction fromeach other. The two segments have a limited mobility. Also, theassociated contact portions in the pair are located in close vicinity toeach other. Therefore, in order to cooperate properly with a codedsurface on a key blade, they must be positioned at approximately thesame level.

In contrast, in the lock according to the present invention, the twobody segments in a pair can be located in many different relativepositions. For each elevational position of one of the body segments,the other body segment can be positioned in various positions.Accordingly, the total number of code combinations is very high.Moreover, since the contact portions of a pair are located relativelyclose to each other, although they are axially separated from eachother, it is very difficult to manipulate one contact portion withoutalso displacing the other one. Therefore, the lock has a very high levelof security against picking.

Many different embodiments are possible within the general inventiveconcept, as set forth in the dependent claims.

The invention also concerns a key blade (and a corresponding key blank)having, at a side surface thereof, a longitudinally extending codedsurface with at least one pair of neighbouring code surface portions(or, in a key blank, at least one material region for cutting out a pairof neighbouring code surface portions) for co-operation with therespective contact portions of a pair of adjacent tumbler body segmentsof a lock as defined above.

The invention will be explained further below with reference to theappended drawings illustrating some preferred embodiments of theinvention.

SHORT DESCRIPTION OF THE DRAWINGS

FIG. 1 shows, in a perspective view, a cylinder lock and key combinationaccording to the invention, in a first, rather simple embodiment havingonly one tumbler assembly, a part of the cylinder shell being cut awayfor clarity;

FIG. 2 shows, in a larger scale, the tumbler assembly included in thelock of FIG. 1;

FIG. 3 shows two separate portions of the tumbler assembly of FIG. 2;

FIG. 4 shows a cross-section of the lock of FIG. 1;

FIG. 5 shows a corresponding cross-section as in FIG. 4, with the keyplug of the lock rotated by an inserted key;

FIG. 6 a shows a cross-section through a second embodiment of the lockwith two tumbler assemblies, one on each side of the key slot;

FIG. 6 b shows a cross-section through a key blade associated with thelock of FIG. 6 a;

FIG. 7 shows a schematical view of a third embodiment of a lock and keyblade with five tumbler assemblies in a row (the rest of the lock is notshown);

FIG. 8 shows a tumbler assembly of a modified embodiment (withspring-loaded tumbler segments);

FIG. 9 shows a cross-section through a lock with a tumbler assembly asshown in FIG. 8;

FIG. 10 shows a longitudinal section through the lock and key blade ofFIG. 7;

FIG. 11 shows a cross-section of a fourth embodiment of the lockaccording to the invention;

FIG. 12 shows a corresponding cross-section as in FIG. 11 with the keyplug rotated by an inserted key blade;

FIG. 13 shows a tumbler assembly included in the lock of FIG. 11separately;

FIG. 14 shows a cross-section of a fifth embodiment of the lockaccording to the invention;

FIG. 15 shows a corresponding cross-section as in FIG. 14, with the keyplug of the lock being rotated by an inserted key blade; and

FIG. 16 shows separately a tumbler assembly included in the lock ofFIGS. 14 and 15.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The lock and key combination shown in FIG. 1 includes a cylinder lock 1and a key 2 with a key blade 200 which is insertable into a key slot 100of the lock. The profile of the key blade 200 is shown in cross-sectionin FIG. 5 and corresponds generally to the profile of the key slot 100.

The cylinder lock is of a similar kind as disclosed in the abovementioned U.S. patent specifications, although it is a simplifiedversion with no centrally located tumblers and only one tumbler assembly110 (see also FIGS. 2 and 3), indicated by dotted lines in FIG. 1. Thetumbler assembly 110 is located at a transversal side of the key slot100, as shown clearly in FIGS. 4 and 5. The tumbler assembly 110 isguided in a cavity 120 located in a cylindrical key plug 130, which isrotatable in a corresponding cylindrical recess 141 in a cylindricalshell 140.

The locking function i.e. the locking of the key plug 130 againstrotation within the cylindrical shell 140 is effected by a fence memberor side bar 150. As illustrated in FIG. 1, the side bar 150 isspring-loaded radially outwardly so as to fit into a longitudinallyextending seating recess 151 (FIG. 5) in the cylindrical shell 140. Theside bar 150 is kept in locking position (FIG. 4) unless the tumblerassembly 110 is positioned in such a way, upon insertion of a properlycoded key blade into the key plug, that the side bar 150 can fit intomutually aligned recesses 111, 112. In the position illustrated in FIG.2, however, these recesses 111, 112 are not aligned and the side bar 150will then be unable to move from its blocking position (FIG. 4).

According to the present invention, the tumbler assembly 110 comprises apair of adjacent tumbler body segments 113, 114 (see FIG. 3), which areguided in the same cavity but are elevationally movable independently ofeach other therein. Because of the separate mobility of these two bodysegments 113, 114, they can be individually displaced so that therecesses 111, 112 become mutually aligned. Now, the side bar 150 can bebrought into the aligned recesses 111, 112, as illustrated in FIG. 5.Thus,upon alignment of the recesses 111,112, the side bar 150 can bemoved into this releasing position by applying a rotating force onto thekey plug 130. Then, the side bar 150 will be forced to move radiallyinwards against the action of the springs 152.

The two tumbler body segments 113,114 preferably have supplementarycross-sections so as to occupy a respective portion of the cavity 120and be guided within this cavity in a well-defined manner withouttilting or rotating relative to the central axis of the cavity. In thisembodiment, the cavity 120 is circular-cylindrical, and the tumbler bodysegments 113,114 have part-cylindrical surface portions being guided bythe cylindrical wall of the cavity 120. The two tumbler body segments113,114 in the pair also have mutually contacting surface portions 113a, 114 a, which permit a relative sliding movement therebetween. In theillustrated embodiment, these mutually contacting surface portions areplanar, but they could have any other geometrical form permitting asliding contact. Also, the cavity may have some other cross-sectionalconfiguration, e.g. rectangular, and the tumbler body segments may beadapted to such a configuration so as to ensure a good guidance withinthe cavity.

The movement of the separate body segments 113, 114 of the lockingtumbler assembly 110 is accomplished by means of the key blade 200having, at a substantially planar side surface 201 thereof, alongitudinally extending coded surface 203 in a groove 202. The groove202 has a bottom wall and upper and lower sidewalls. The lower sidewall203 forms a wave-like coded surface, which in this embodiment includestwo neighbouring code surface portions 204, 205. These code surfaceportions 204, 205 are designed to receive a respective contact portion,in the form of an outwardly projecting finger 115, 116, on each tumblerbody segment 113,114. In the illustrated embodiment, each contactportion or finger has a relatively wide base portion 115 a and 116 a,respectively, and a relatively narrow, substantially cylindrical freeend portion 115 b and 116 d, respectively. When the key blade 200 isinserted into the key slot 100 of the lock 1, the fingers 115, 116 willbe positively guided in the groove 202. In the fully inserted position,the fingers 115, 116 will be located in the neighbouring code surfaceportions 204, 205, so that the recesses 111, 112 are aligned, the sidebar 150 may be displaced into these recesses upon applying a rotarytorque onto the key plug 130, whereupon the latter can be rotated byturning the key 2, as shown in FIG. 5.

In the illustrated embodiment, the longitudinal groove 202 hassubstantially parallel upper and lower sidewalls so as to positivelyguide the respective fingers 115,116. Alternatively, the groove 202 maybe much wider than the diameter of the end portion 115 b, 116 b of therespective finger. In the latter case, the fingers are preferablyspring-loaded (see FIGS. 8 and 9) so as to engage slidingly with thelower coded sidewall 203 and the coded surface portions 204, 205.

In the second embodiment of the lock and key combination, as illustratedin FIG. 6 a, the key blade 200′ (FIG. 6 b) is provided with grooves 202′on each lateral side. These grooves may be undercut, if so desired (seealso FIGS. 11 and 12).

In the lock of FIG. 6 a, there is a cavity 120,121 on each transversalside of the central key slot 100 in the key plug 130. In each cavity120, 121, there is a tumbler assembly 110 comprising two independentlymovable body segments 113, 114 of the kind shown in FIGS. 2 and 3. Eachtumbler assembly 110 co-operates with a side bar 150 in the mannerdescribed above.

In the embodiment of FIG. 6 a, the key blade 200 (FIG. 6 b) issymmetrical, so that it can be turned upside down and still workproperly in co-operation with the key slot 100 and the fingers 115, 116of the respective tumbler assemblies 110.

As illustrated in FIG. 7, the lock may have a longitudinal row oftumbler assemblies 110 (five in a row), each tumbler assembly having apair of independently movable body segments 113, 114 with associatedcontact portions or fingers 115, 116. When the key blade 200 is insertedinto the lock, all the fingers 115, 116 will be positively guided by thelongitudinally extending coded groove 202, which in this case has tendifferent code surface portions each being located at a specific codelevel. These code surface portions 204, 205 are grouped into five pairseach comprising two neighbouring code surface portions 204, 205. For aspecific level of a code surface portion 204, the neighbouring codesurface portion 205 may be located in at least two or possibly three,four, five or even a higher number of different levels. Accordingly, thetotal number of code combinations will be very great. Of course, thetotal number of code combinations may be substantially increased by alsoproviding an ordinary code pattern at the longitudinal top edge surfaceof the key blade 200, as indicated by the numeral 206 in FIG. 7. Even inthis third embodiment with a longitudinal row of tumbler assemblies 110,there may be such a row on each transversal side of the key slot of thelock (similar to the embodiment illustrated in FIG. 6 a).

As indicated above, each body segment 113, 114, may alternatively bespring-loaded, as indicated in FIGS. 8 and 9, by means of helicalsprings 117 seated in holes 118 at the top end of each body segment 113,114. In FIG. 9, there is also shown, in the key slot 100, a centraltumbler 131 (one in a longitudinal row of such tumblers) co-operatingwith the coded cuts or dimples 206 in the edge portion of the key blade200.

In the partial longitudinal section shown in FIG. 10, the respectivebody segments 113, 114 and the associated wider finger base portions 115a, 116 a are visible as is the key blade 200. In order to lock the keyplug 130 against rotation within the cylinder shell 140, it is possible(see FIGS. 11 and 12) to use top tumblers or pins 113′ (not shown) and114′, which stay in contact with and follow the associated body portions113, 114. In a specific elevational position, as illustrated in FIG. 12,the body segment 114 and the associated top pin 114′ have their mutuallyengaging surfaces located in the shear line, whereby the key plug 130can be rotated in the shell 140.

In this fourth embodiment, the key blade 200 has an undercut groove 202″co-operating with a corresponding profile tongue 132 having a downwardlyprojecting portion 133 fitting into the undercut portion of the groove202″ of the key blade.

In all embodiments and modifications described above, there is at leastone tumbler assembly 110 comprising a pair of body segments 113, 114being elevationally movable independently of each other while engaging(with its associated contact portion or finger 115, 116) the codedgroove 202 of the key blade 202, when the latter is inserted into thelock. A very great number of code combinations is obtainable, and thelock has a very high security against picking, as explained above.

Further modifications are possible within the scope of the claims. Thetumbler body portions 113, 114 are illustrated to be substantiallyhalf-cylindrical with two mutually engaging, substantially flat surfaces113 a, 114 a (FIG. 3). Of course, other geometrical shapes are alsopossible as long as the two body portions are properly guided within theassociated cavity 120 and are capable of moving independently of eachother while being engaged, by way of the contact portions or fingers,with the coded surface at the key blade.

The key blade can be furnished with coded bittings and/or dimples onother surfaces corresponding to tumber mechanisms of various kinds, suchas coded dimples on the respective edge portions of the key blade ofFIG. 6 b cooperating with centrally located pin tumblers (not shown) inFIG. 6 a.

Instead of a groove 202, the coded surface may be formed on a stepsurface or shelf forming a transition between a massive base portion ofthe key blade and an upper, narrower portion thereof.

The outwardly projecting finger 115,116 does not have to be located atan end portion of the associated tumbler but could be located somewherebetween these end portions. Such an embodiment is shown in FIGS. 14, 15and 16. Here, the tumbler segments 114 have a length (or height)corresponding to the key plug 130. The cavity 120 adjoins correspondingcylindrical cavities in the shell 140. The tumbler segment 114 locks thekey plug against rotation, unless it is located exactly in the positionshown in FIG. 15. Then, the key plug can be rotated by turning the keyblade 200.

Furthermore, the contact portion of the tumbler body segment 113,114does not have to be formed as a finger but may have any othergeometrical shape as long as the contact portion reaches into the keyslot so as to engage with the coded surface of the key blade. Also, thecontact portion does not have to project outwardly sideways. It may evenform a part of the (cylindrical) tumbler body segment itself.

As indicated above, the cavity may have a different cross-sectionalshape, such as elliptic, rectangular or polygonal, and the two tumblerbody segments should then be adapted to such a configuration.

The cavities (and the direction of elevational movement of the tumblerportions) may have any suitable angle (0-90 degrees) to the centralplane of the key slot.

Moreover, the locking mechanism as defined in the claims may be combinedwith other locking mechanisms in the same lock. One locking mechanism,according to the invention, may be provided on one transversal side ofthe key slot, whereas another mechanism, possibly also in accordancewith the present invention, may be arranged on the other transversalside of the key slot. As indicated above, conventional locking tumblerpins may also be located centrally above the key slot. While the mostpractical embodiment of the invention (from a manufacturing andtolerance point of view as well as operational reliability) it ispreferred that each locking tumbler assembly consists of a pair oftumbler segments, it is conceivable to add an intermediate or thirdtumbler segment therebetween.

1. A cylinder lock (1) and key (2) combination, said key (2) comprisinga key blade (200) having, at a side surface (201) thereof, alongitudinally extending coded side surface (203) with longitudinallyspaced code surface portions each representing an element of a key code,and said cylinder lock (1) comprising a cylinder shell (140), a key plug(130) which is rotatably mounted in said shell, a longitudinal key slot(100) extending along said key plug in parallel to the rotational axisthereof for receiving said key blade (200), at least two side tumblers(113, 114) in said key plug for locking said key plug against rotationrelative to said cylinder shell, unless a correctly coded key isinserted into said key slot, each side tumbler being provided with acontact finger (115, 116) reaching sideways into said key slot so as toengage with said coded surface (203) of a properly shaped key bladebeing inserted into said key slot, and at least one side cavity (120)located at a transversal side of said key slot (100) in said key plug(130), said at least one side cavity accommodating and guiding said sidetumblers for elevational movement therein, wherein: said at least twoside tumblers are distributed pair-wise, with two adjacent side tumblers(113, 114) located in a respective side cavity on the same side of saidkey slot, said adjacent side tumblers (113, 114) in each pair beinglinearly guided but independently movable in the respective side cavityso as to be individually displaced linearly into respective elevationalpositions, and said contact fingers (115, 116) on the adjacent sidetumblers in each pair having contact portions facing in the samedirection and being axially separated in the longitudinal direction ofthe key plug such that these contact fingers are located at alongitudinal distance from each other on the same side of said key slotand will be positioned at elevationally specific and generally differentcode levels when being engaged by two neighbouring, longitudinallyspaced code surface portions (204, 205) of said coded surface (203) uponinsertion of said key blade (200) into said key slot (100), whereby saidat least two side tumblers (113, 114) are displaceable, upon insertionof said key blade into said key slot, into individually specificelevational code positions, and each set of such elevational codepositions representing a different key code with an increased number ofcode elements, a pair of side tumblers corresponding to two codeelements.
 2. A cylinder lock and key combination as defined in claim 1,wherein a body segment (113, 114) of each side tumbler in each pair isguided in a respective portion of said at least one side cavity (120),the contact fingers (115, 116) of these side tumblers in said pairprojecting outwardly in parallel from said side cavity into said keyslot.
 3. A cylinder lock and key combination as defined in claim 2,wherein said pair of adjacent side tumbler body segments (113, 114) havesupplementary cross-sections, which together substantially correspond tothe cross-section of said cavity (120).
 4. A cylinder lock and keycombination as defined in claim 3, wherein said adjacent side tumblerbody segments (113, 114) of said pair being substantially defined byhalf-cylindrical surface portions being guided by wall portions definingsaid cavity (120).
 5. A cylinder lock and key combination as defined inclaim 3, wherein said adjacent side tumbler body segments of said pairhave mutually engaging surface portions (113 a, 114 a) being in slidingengagement with each other.
 6. A cylinder lock and key combination asdefined in claim 5, wherein said mutually engaging surface portions (113a, 114 a) are substantially planar.
 7. A cylinder lock and keycombination as defined in claim 1, wherein said key plug (130) containsa row of side cavities (120), each such side cavity accommodating a pairof adjacent, independently movable side tumbler body portions.
 8. Acylinder lock and key combination as defined in claim 1, wherein saidkey plug (130) includes at least one pair of locking tumblers (113, 114)in a side cavity (120) on each transversal side of said key slot (100).9. A cylinder lock and key combination as defined in claim 1, whereinsaid at least two side tumblers (113, 114) cooperate with a side bar(150) being accommodated in a longitudinal recess (151) in said cylindershell (140), said side bar (150) being adapted to normally lock the keyplug against rotation in said shell and to be displaceable into areleasing position upon insertion of a properly coded key blade (200)into said key slot (100).
 10. A cylinder lock and key combination asdefined in claim 2, wherein said contact fingers (115,116) arepositively guided in a longitudinally extending groove (202) of said keyblade.